Colorado Senator Cory Gardner’s bid to include marijuana reform in the U.S. Senate’s new criminal justice reform bill fell flat this week after his fellow Republicans blocked his proposed amendment to the First Step Act.

The amendment, which was very similar to legislation Gardner filed this year with Sen. Elizabeth Warren (D-MA), was called a “back door to legalization” by Sen. Chuck Grassley (R-Iowa). Senate Majority Leader Mitch McConnell, who had the task of maintaining accord on the bill, was able to block Gardner’s reform effort with a procedural move.

Gardner and other supporters of federal marijuana reform legislation say they are not discouraged. The Colorado senator plans to reintroduce his reform bill during the next Congress.

“We’re the opposite of feeling defeated. We’re feeling energized,” Cannabis Trade Federation CEO Neal Levine told the Denver Post. “We just had a U.S. senator, who is in a leadership position in his party, say on the floor of Congress that he’s not going to give up this fight.”

Congress passed the First Step Act on Tuesday night. President Donald Trump is expected to sign the criminal justice overhaul sometime this week.